1. Field of the Invention:
The present invention relates to a method of producing a bleached, dried fruit, and more particularly to such a method for use in the field in which fruit is subjected to the products of combustion from burning sulfur and subsequently dried by solar radiation having the visible light rays filtered therefrom.
2. Description of the Prior Art:
It has, of course, long been known to dry fruit by solar radiation, as in the production of raisins from grapes. Such sun dried raisins are produced in a well-known manner simply by disposing bunches of freshly picked grapes on paper trays placed on the ground in the vineyards between rows of grapevines. While so disposed, the grapes are dried by exposure to the rays of the sun without the application of additional heat. However, raisins so produced by this process are dark in color, being substantially black, even though the grapes are light greenish or yellowish in color, as picked. While such raisins are popular, there exists a large and well recognized demand for bleached or golden raisins.
Such bleached raisins are relatively expensive because of the additional labor, equipment, and energy required in their production as compared with the sun drying of grapes to produce dark raisins. Also, the relative complexity of the conventional process for producing bleached raisins and the amount of capital required to purchase the equipment needed makes it essentially a plant operation. In fact, insofar as the applicant is aware, bleached raisins had never been produced in the fields or vineyards prior to the present invention. Thus, the conventional process requires the grapes to be picked and transported to a properly equipped plant. At such a location, the grapes are first immersed in a tank containing an aqueous sodium hydroxide solution minutely to crack the skins. The grapes are then washed repeatedly to remove all traces of sodium hydroxide. The grapes are then placed in a "sulfur house" which is a substantially air-tight room in which sulfur is burned. The grapes are subjected to sulfur dioxide fumes from the burning sulfur for a period of time. The grapes are then dried artificially into raisins in a dehydrator which, typically, is heated by fossil fuel. Prior to the present invention, it was considered necessary to perform such drying artificially since exposure to solar radiation of the grapes which have previously been subjected to the sodium hydroxide solution and then sulfur dioxide causes such grapes to darken resulting in unbleached raisins.
As can be seen, this previously known process for producing bleached raisins requires that the grapes be handled many more times than in the production of ordinary, dark raisins. The conventional bleaching process requires a dehydrator, which is relatively expensive as is the fuel required for its operation. A sulfur house must be provided at additional expense.
As will subsequently become apparent the process of the present invention for the first time permits the field production of bleached raisins, minimizes handling and labor, requires no immersing tanks of sodium hydroxide, requires no rinsing to cleanse the grapes of sodium hydroxide before drying, requires no sulfur houses, and requires no fuels for dehydration.